The present invention relates to a charge control device that limits upper limits of a charging current and a charging voltage according to a battery temperature, a battery pack provided with this charge control device, and a charger.
As illustrated in FIGS. 12A and 12B, in a battery such as a lithium-ion battery, a temperature range of the battery is classified into a low temperature range (T1-T2), an ordinary temperature range (T2-T3), and a high temperature range (T3-T4), and upper limits of a charging current and a charging voltage are defined for each range (see, for example, Japanese Unexamined Patent Application Publication No. 2009-55729, etc.).
A reason for setting the upper limits is to ensure safety during charging, as well as to inhibit a life span of the battery from being shortened due to charging. During charging, the battery is charged with a charging current equal to or lower than the upper limit obtained from a charging current characteristic and a battery temperature shown in FIG. 12B. Then, when a battery voltage reaches the upper limit obtained from a charging voltage characteristic and a battery temperature shown in FIG. 12A, the charging of the battery is stopped.